Cells, tissues, microorganisms and other biological materials and substances, collectively and generally referred to hereinafter as "biological materials", frequently have to be treated for growing of cultures and the like. Some of these substances require sterilization before being subjected to treatment. Incubators and other containers have been provided in which predetermined temperature and humidity conditions are maintained. The gas atmosphere within the containers can also be controlled, for example by controlling the oxygen content or admitting other gases such as CO.sub.2, nitrogen, pure oxygen, or the like. In one such apparatus, temperature and humidity are controlled and maintained at an essentially constant level by saturating gases or air admitted into the container with water vapor. To provide the necessary humidity, a water boat or vessel, or a sump, is placed in the container in which a predetermined water level is established.
It has been found that maintaining a vessel with water within the treatment area of the container or incubator, for example, in short the cultivation space, may introduce the danger of contamination by fungi or bacteria for the cultures to be treated due to the relatively high humidity within the cultivation space.
Reference is made to prior patents, and specifically U.S. Pat. No. 3,941,662, Div. of 3,873,423, which describes a process of the type to which the present invention relates; U.S. Pat. No. 4,142,940, and German Utility Model DE-GM No. 72 383 51 which, respectively, show incubating containers suitable for use with appliances and devices of the type to which the present invention relates.